TRH and GnRH have been identified in extrahypothalamic loci throughout the human CNA. The identity of exogenous TRH with synthetic TRH was corroborated by four independent criteria, including immunologic identity, Sephadex column chromatography, biologic assay in vitro, and deamidation kinetics by human plasma TRH degradating activity. TRH has been located also in human hypothalamic nuclei by micropunch biopsies, including supraoptic paraventricular, mammillary body, and median eminence regions. An innovative methodology has been developed for investigating TRH biosynthesis in vitro. Rabbit anti-TRH IgG has been covalently linked to Sepharose 4B by cyanogen bromide activation. 3H-proline was used as a TRH precursor in KRB. TRH de novo biogenesis was demonstrated in two extrahypothalamic sites; i.e., cerebral cortex and pineal gland. It is proposed to extend ongoing studies of TRH metabolism in the human brain and in isolated rat hypothalami in vitro. The content on somatostatin in 26 anatomic loci, in relation to TRH and GnRH will be investigated. The impact of neurologic disease states upon the content of TRH and GnRH will be examined. Studies of TRH biogenesis and metabolism will include: 1) examination of synthetic mechanisms; 2) influence of neurotransmitters upon TRH synthetic rates; 3) biological determinants of TRH formation, such as age, sex, and diurnal rhythms; 4) neuroanatomical localization of TRH synthetic capability and 5) hormonal influences upon TRH metabolism, including T4, T3 and corticosterone. BIBLIOGRAPHIC REFERENCES: Kubek, M.J., Lorincz, M.A., and Wilber, J.F.: The identification of thyrotropin releasing hormone (TRH) in hypothalamic and extrahypothalamic loci of the human CNS. Brain Research. In press, January, 1977. Berlinger, F.G., Ruder, H.J., and Wilber, J.F.: Cushing's syndrome associated with galactorrhea, amenorrhea, and hypothyroidism: a primary hypothalamic disorder. J. Clin. Endocrinol. Metab. Accepted for publication, 1977.